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Polar Alignment is
the star alignment method I use the most. I used to use a Meade #883 tripod
for my Meade ETX-90EC. Meade #883 tripod has a poorly designed leg clamps.
Polar alignemt is very easy on the meade #883 tripod. The Meade #883 tripod
has all the micro adjustment for Polar Alignment. If not for the leg clamp,
it is perfect for the Meade ETX-90EC or smaller telescopes. After I bought
my Meade ETX-125EC, I found the Meade #883 Tripod is too small for the
Meade ETX-125EC telescope. At 18lb, the leg clamps would slip and the
tripod could collapse. I soon sold the Meade #883 tripod.
Polar Alignment is not possible with a Meade #884 tripod! Well, I did
not know that. When the Meade #884 deluxe field tripod came out and I
bought one. I returned the Meade #884 deluxe field tripod to the store
where I bought it in less than a week. Since I do 80% of my observations
in the Polar alignment position, the Meade deluxe field #884 tripod will
not work at all. There is no precision micro adjustment on the Meade #884
deluxe field tripod at all. It can be use only in the ALT/AZ position.
Polar alignment is important to me but It is impossible to perform a Polar
alignment with the Meade #884 deluxe field tripod.
My tripod is custom made from a surveyor's tripod, a Celestron tripod,
and a Meade Equatorial tripod head and a custom leveling platform.
The surveyor's tripod
is a very sturdy, strong and yet inexpensive. It stand about 4 feet to
over 6 feet tall. I bought it from Home Depot for about $60.00.
The azimuth movement
of the Polar mount head is from my old Celestron tripod. The Altitude
adjustment part is from a Meade Equatorial mount. I cut, grind these two
parts together. The azimuth movement allow precision micro adjustment
of horizontal turn of the telescope without moving the tripod legs. The
Altitude adjustment allow precision micro adjustment of altitude.
I designed the leveling
platform. The leveling platform allows me to level the telescope by just
turning two machine screws. One to level left to right, the other to level
front to back. I never have to bend down to change the length of the leg.
The leveling platforum
consists of two aluminum plate. The bottom plate is attached to the top
of the tripod with three machine screws. The top plate is fitted with
three joint bearing. The joint bearings allow the bearing axis to swing
up to 15 degrees to the side. Each of the machine screw is fixed to the
bearing with a wingnut and a hexnut. The machine screw can turn freely
with the turn of the wingnut. The bottom plate is taped with 1/4"
20 thread. I can turn the wingnut on top plate to raise or lower the top
plate. I I would place a bubble level for leveling left to right, another
one for front to back. It would take me seconds to level the top of the
platform by turning the wingnuts standing upright.
Polar alignment is easy with my custom tripod.
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